The present invention relates to a network protocol processing device, and more particularly to TOE (TCP/IP Offload Engine) equipment that specializes in network protocol processing of a host computer whose resources are virtually parted on a user basis, and a server equipped with it.
TCP/IP (Transmission Control Protocol/Internet Protocol) is known as a communication protocol most widely used for network communications among computers, including the Internet. However, TCP/IP, particularly TCP protocol, imposes a heavy load on a host processor because of the complexity of processing for the protocol.
Network communication technologies in recent years, particularly speed-enhancement technologies for Ethernet (Ethernet is a trademark of Xerox Co.) have advanced so remarkably that 1-GbE Ethernet with a transfer speed of 1 gigabits/s has recently become a mainstream. Furthermore, in next several years, 10-GbE Ethernet with a transfer speed of 10 gigabits/s is expected to become prevalent.
In general, it is said that 1 Hz worth of CPU processing capability is necessary for TCP/IP data transfer of 1 bit/s. According to this estimate, a processor processing capability of about 10 GHz is required for TCP protocol processing of 10 Gbit/s. However, a clock frequency of general processors will stay at several gigahertz at a time when 10 GbE becomes prevalent in several years. The processing capability will not be sufficient for processing of 10 GbE. In other words, data cannot be transferred with a band width, which determines physical performance of a network. Or, a host processor may cause a delay in primary service tasks to be done because of protocol processing overhead.
Therefore, attention is directed to a dedicated hardware device that performs (offloads) TCP protocol processing in place of a host processor. This device is called TOE (TCP/IP Offload Engine). The TOE equipment can be installed in a server to concentrate on network protocol processing. This contributes to good network performance and reducing loads on the host processor so that an increase in service processing performance, which is a primary objective of the host processor, can be achieved.
As technologies concerning the TOE equipment, for example, in Japanese Published Unexamined Patent Application No. 2001-268159 (Patent Document 1), a device that processes TCP/IP by hardware, that is, TOE equipment and its operation method are disclosed. In addition, in Japanese Published Unexamined Patent Application No. 2001-339462 (Patent Document 2), a communication protocol processing method by the TOE is disclosed. Furthermore, in U.S. Pat. No. 6,427,173 (Patent Document 3), U.S. Pat. No. 6,334,153 (Patent Document 4), and U.S. Pat. No. 6,591,302 (Patent Document 5), examples of TCP/IP offload engine are disclosed.
In U.S. Unexamined Patent Publication No. 2003/0135578 (Patent Document 7), there is disclosed a server connected to plural networks, wherein an independent private address space is defined in each of the networks, and wherein the server is a virtual server having plural logical spaces. This server provides independent services for each of IP address identifiers (Space-ID) of the networks.